Rheost



Aug. 2s, 19.212. 1,682,113

H. D. BROWN l RHEOSTAT Filed April 8, 1926" 3 Sheets-Sheet l OOOOOOOOOOOGO O OOOOO OOO()4 Aug. 28, 1928. 1,682,113

v H. D. BROWN RHEOSTAT Filed April 8,I 1926 5 Sheets-Shen 2 Aug.'28,192s. 1,682,113

H. D. BROWN l v I RHEOSTAT Filed April 8, 1926 5 Sheets-Sheet 3 Innen/0r pfff/vra 6kg.

l provide a circular bottom plate 33 (coaxial with andfcentrally apertured at 34 to take post 14) which is adapted to rest on the radially spaced lugs 35 and 36 provided on the upper side of eachl casting arm 15, the inner lugs 36 having threaded bores -37 adapted to 'take bolts 38.

, Plate 33 has an annular, upwardly, ex-

tending flange 89'near its outer edge, and

has upper and lower bosses 4() which-are in Y alignment with bosses 36. A bottom bus ring B, of material such `as cast brass or other metals having suitable Vcurrent-conductive characteristics, has 'downwardly extending bosses 4l which are arranged to be in vertical alignment with bosses 36 and 40, lbut insulating washers 42v are interposed between bosses 41 and plate 33. Anchor bolts 38 pass, preferably with considerable clearance, through a1 bus-ring bosses 41, and thence through washers 42 vand plate 33 intoy bosses 36, the heads Y of the bolts being insulated from the bus rings by washers 43. Bolts 38 hold casting 10, plate 33 and bus ring B Ain assembly, but it will be seen that the bus ring is entirely insulated from plate 33, casting 10 and post 14; the central opening 44 of the bus ring being of considerably greater diameter than V.that of post 14so that there may bean ample air gap betwecnring and post.

' Extending upwardly from and integral ly right angles with respect to andl from opposite sides. of said mainplate, said trans-v k verse plates preferably being located approximately midway betweenthe edges 48 of the main plate.V Therefore, considered in transsov verse cross-section the plates have the configuration of a cross with a pair of oppositely disposed long arms and a pair of oppositely disposed and centrally disposed short i arms. The plates are made of any material having suitable non-current-conductive characteristics (I find transite tobe particularly vwell suited to the purpose) and their exposed edges are preferably serrated as at 49 to provide grooves wherebythe coils of resistance wire 50, wound spirally about the rack, may be kept separated. The wirel 50,

having' characteristics usual to resistance wires of rheostatsfis wound with suflicient` tensionpto retain it in contact with the exposed edges, only, of the plates, the major extent of the wire thus being held from the plates, with obvious advantage.

The opposite ends of the wire spiral are4 given pair having oppositely opening sockets 56 having the same horizontal cross-sec- `tion characteristics of the rack, that is, the

sockets have relative long portions 57 adapted to take the opposite ends of plate 46 and have relatively short transverse portions 58 adapted to take the oppositeends of plates 47. Vhile the ends of all the vplates may have friction tight tit within the caps, I preferably provide bolts 59 through the caps and main Y plates so the caps may be held positively `from displacement with respect tothe rack.

Y Extending from the top and bottom, respectively, of the upper and lower terminal caps, are attachment lugs 60 which are preferably slotted at 61 to take bolts 62, the latterl being adapted releasably to'draw. lugs Y 60 into tight-facial engagement, and there- .fore electrical connection with the associated lugs 45 vor 45 of bus rings B and B, respectively, said ring B being similar to ring B but being reversed, top for bottom, so itslugs 45 extend downwardly. The terminal caps are thus releasably secured in electrical vconnection with their associated bus rings 'and current may pass from aV given bus ring, through wire 50 and` thence to the other bus ring. Itwill also be apparent that bolts 62 form the connection whereby the` wire racks are supported by the bus rings. Bus lring YB is suspended by bolts 38a froma top plate 63 which is generally similar to bottom plate 33 vexcept thatits annular flange 64 extends downwardly, and ithas a central hub 65to take post 14.; a set screwv66 or equivalent means preferably being provided through the hub and adapted to engage post' 14 frictionally so the top plate and top bus ring are held releasablyy in spaced relation along the post with respect to the-bottom plate and bus ring. f I I Bolts 38a are insulated from' ring-B by air gap 67 and washer 68, while said ring' is insulated from plate 68 by a ring 69 ofinsula-ting material such as transite. .Y u

It'will be seen that the resistance elements and bus rings are entirely insulated from the supporting standard or frame F. p Y Extending about the rheostat is a metalcasing C which preferably is perforated-at 70 to provide ventilation, thecasing being in the lou form of a band Vdrawn around flanges 39 and 64, with its free ends overlapped and detachably secured together as by screws 71 (Fig. 1).

Should the wire of a given element break or burn out, it will be seen that it is a mat-ter of ease to strip the casing from Athe rheostat, detach the defective element from the bus rings, and replace it; all without in any way dis- .turbing such elements as are in good order. Not only is a saving in time thus effected, but Wire is also saved, since only a portion of the total Wire length of the rheostats need be replaced.

Wires IV lead from lamp switch 72 through insulating bushings 7 3 in plate 63 and extend one to each of bus rings B and B. The Wires may be clamped in electrical connection to the rings by any suitable means, preferably easilyreleasable; for instance, by clips 74 which are screwed to rings.

It is believed a full understanding of the invention will be hadfrom the foregoing, but the draWingsfand description are to be considered merely as illustrative of and not restrictive on the broader claims appended hereto, for various changes in design, structureand arrangement may be made Without departing from the spirit and scope of said claims.

y I claim:

1. In combination With the support-ing frame of a lamp which frame includes a base member having a substantially centrally arranged, vertical post; a rheostat embodying a pair of bus rings spaced apart longitudinally along and insulated from the post, and a plurality of angularly spaced resistance elements arranged abouty the post, each element embodying a'ivire-rack having non-conductive characteristics, spaced terminals on said f rack, andresistance Wire Wound'about said rack between and terminally connected to said terminals; and detachable means electrically connecting the terminals, one to each of the bus rings, said detachable means also serving as connections through Which the racks are supported by the bus rings.

2. In combination With the supporting frame of a lamp which frame includes a base member having a substantially centrally arranged,'vertical post; a rheostat embodying a pair of bus rings spaced apart longitudinally along and insulated from' the post, and a plurality of angularly spaced resistance elements' arranged about the post, each element embodying a Wire-rack having non-conductive characteristics, terminal caps applied to Vopposite ends of the rack, said caps having conductive characteristics, and resistance Wire Wound about said rack between and terminally connected to said caps; and detachable means electrically connecting the caps, I

one to each of the bus rings, said detachable means'also serving as connectionsV through which the racks are supported by the bus rings.

In Witness that I cla-im the foregoing I have hereunto subscribed my name this 23rd dayof March 1926. l

' HARRY D. BROWN. 

